Recording medium having data structure for managing reproduction of text subtitle and recording and reproducing methods and apparatuses

ABSTRACT

In the data structure for managing reproduction of text subtitle data, a recording area stores a main file and at least one separate text file. The main file includes multiplexed audio and video data streams, and the text subtitle file includes a single text subtitle stream.

PRIORITY STATEMENT

This application is a Divisional of co-pending application Ser. No. 10/960,486 filed on Oct. 8, 2004 and from which priority is claimed under 35 U.S.C. §121. The application also claims priority from Korean Patent Application No. 10-2003-071396, filed on Oct. 14, 2003, in the Korean latent Office under 35 U.S.C. 119. The entire contents of these two applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to high density recording media such as optical discs, and in particular, blu-ray read-only discs.

2. Description of the Related Art

Optical discs that are capable of storing large amounts of high-quality video and audio data, have been available on the market. The digital versatile disc (DVD) is one example of such an optical disc. Recently, DVD players and DVD recorders have been available on the market and have become one of the most popular consumer electronic products.

Subtitle data that is to be displayed on screen as characters or logo during playback of video data (e.g., a movie) is generally recorded on a DVD in the bitmapped format. While the main video data recorded on the DVD is reproduced, the bitmap-formatted subtitle data is read out from the DVD and output to an external display device such as a TV after a series of signal processing steps so that the bitmap subtitle is displayed on the screen of the external device. In this way, a user can watch subtitles or logo on the screen of a TV during playback of a DVD title.

Recently, the standardization of new higher density optical discs; for example, blu-ray read-only disc (BD-ROM) has been under development. An effective method of reproducing the subtitles recorded on a BD-ROM in a various ways has not been established.

SUMMARY OF THE INVENTION

A recording medium according to the present invention includes a data structure for managing reproduction of text subtitle data.

In one embodiment, the recording medium stores a main file and at least one separate text file. The main file includes multiplexed audio and video data streams, and the text subtitle file includes a single text subtitle stream.

In one embodiment, the text subtitle file stores the text subtitle stream as transport packets, and each transport packet in the text subtitle stream has a same packet identifier.

In another embodiment, the main file also stores the multiplexed audio and video data streams as transport packets. Here, the packet identifier of the text subtitle stream is distinguishable from packet identifiers for the transport packets in the main file.

In a further embodiment, the main file includes multiplexed audio data, video data and bitmap streams. For example, in one embodiment, the bitmap stream is a bitmap subtitle stream.

The present invention further provides apparatuses and methods for recording and reproducing the data structure according to the present invention. For example in a method of reproducing a recording medium having a data structure for managing a text subtitle, the method includes loading, from the recording medium, a text subtitle file into memory before decoding of a text subtitle stream included in the text subtitle file. Here, the text subtitle file is stored separately from a main file on the recording medium. The main file includes multiplexed audio and video data streams, and the text subtitle file includes a single text subtitle stream.

An example apparatus includes at least a pick-up, a memory and a text processor. The pick-up is for reproducing at least one text subtitle file from the recording medium; the text subtitle file being stored separately from a main file on the recording medium. The main file includes multiplexed audio and video data streams, and the text subtitle file includes a single text subtitle stream. The memory is for storing the reproduced text subtitle file, and the text processor is for decoding the text subtitle stream stored in the memory.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate the exemplary embodiments of the invention, and together with the description, serve to explain the principles of the present invention. In the drawings:

FIGS. 1 to 6 illustrate embodiments of the present invention showing various configurations of bitmap-formatted subtitle stream and text-form subtitle stream on a BD-ROM;

FIGS. 7 to 12 illustrate embodiments of the present invention showing different writing schemes of a plurality of text subtitle streams separately from a main A/V stream;

FIG. 13 illustrates a block diagram of an embodiment of the optical disc reproducing apparatus according to the present invention; and

FIGS. 14 to 16 illustrate block diagrams of embodiments of partial components of the optical disc reproducing apparatus according to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In order that the invention may be fully understood, exemplary embodiments thereof will now be described with reference to the accompanying drawings.

For an optical disc such as blu-ray read-only disc (BD-ROM) in accordance with the present invention, subtitle data is recorded thereon so as to provide the subtitles associated with main audio and video (A/V) data. The subtitle data is bitmap-formatted or in text form (e.g., character codes). Hereinafter, these two types of subtitle data will be referred to as bitmap subtitle data and text subtitle data, respectively. Both bitmap subtitle data and text subtitle data may be recorded on the optical disc, or either, or neither. Before being recorded on the optical disc, the subtitle data may be multiplexed with the main A/V data.

The bitmap subtitle data or text subtitle data may be supplied from a content provider server (CP server) through networks such as the internet. The text subtitle data from the CP server is transmitted in the MPEG2 transport stream (TS) format or extensible markup language (XML) format. A plurality of the text subtitle data may be sent from the CP server so as to supply subtitles for several different language. Moreover, another type of data stream such as an audio stream may be supplied from the CP server together with the, subtitle data.

According to the present invention, the text subtitle data and bitmap subtitle data may be organized on a BD-ROM in different ways, which will be described hereinafter in detail.

In a first embodiment shown in FIG. 1, both a bitmap subtitle stream and a text subtitle stream are recorded on a BD-ROM as a main subtitle and an auxiliary subtitle, respectively. The bitmap subtitle stream is multiplexed with a main A/V stream and then recorded as a main MPEG2 TS clip file on the BD-ROM. On the other hand, the text subtitle stream is recorded as a text subtitle file separately from the main MPEG2 TS clip file.

When reproduced, the text subtitle stream is uploaded on to a hard disk drive (HDD) or other memory such as a RAM, flash memory, etc., and is then decoded by a text processor (discussed in detail below with respect to FIG. 13). Or, the text subtitle stream may be decoded directly by the text processor without uploading.

The bitmap subtitle stream is recorded on the BD-ROM in a transport packet (TP) format, where the transport packets have a unique packet ID (PID) distinguishable from the PIDs of the main A/V stream. As shown in FIG. 1, the text subtitle and the bitmap subtitle may be used for subtitles of different languages such as Korean and English. While seamless reproduction between the bitmap subtitle and the text subtitle is possible, whether seamless reproduction between the text subtitle streams may be supported or not depends on the optical reproducing apparatus.

In a second embodiment shown in FIG. 2, both a bitmap subtitle stream and a text subtitle stream are recorded on a BD-ROM in such a way that both streams are multiplexed with the main A/V stream and then recorded as a main MPEG2 TS clip file on the BD-ROM. Both streams are recorded on the BD-ROM in a TP format. The transport packets of each stream have a unique PID distinguishable from PIDs of the main A/V stream. When reproduced, both streams are directly decoded by a text processor without loading into memory in the optical reproducing apparatus.

As shown in FIG. 2, the text subtitle and the bitmap subtitle streams may be used for different languages such as Korean and English. While seamless reproduction between the bitmap subtitle and the text subtitle is possible, whether seamless reproduction between the text subtitle streams may be supported or not depends on the optical reproducing apparatus.

In a third embodiment shown in FIG. 3, the main A/V stream is recorded on a BD-ROM, for example, as a main MPEG2 TS clip file without the bitmap subtitle and the text subtitle stream being multiplexed therewith. The text subtitle stream is recorded as a text subtitle file separately from this main file.

When reproduced, the text subtitle stream is uploaded on a hard disk drive (HDD), or other memory such as a RAM, flash memory, etc., and then decoded by a text processor. Or, the text subtitle stream may be decoded directly by the text processor without uploading.

As shown in FIG. 3, the text subtitle streams for different languages such as Korean and English may be recorded as distinct text subtitle files (text subtitle files #1 and #2, shown in FIG. 3), or may be recorded as distinct streams within a text subtitle file such that seamless reproduction between text subtitle streams of different languages may be performed.

In a fourth embodiment shown in FIG. 4, the text subtitle stream only is multiplexed with a main A/V stream and then recorded as a main MPEG2 TS clip file on a BD-ROM. The text subtitle stream is recorded in a TP format, where the packets have PIDs distinguishable from the PIDs of the main A/V stream. When reproduced, the text subtitle stream is directly decoded by a text processor without loading into a memory in the optical reproducing apparatus.

As shown in FIG. 4, the text subtitle streams for different languages have distinct PIDs such that seamless reproduction between the text subtitle streams of different languages may be performed.

In a fifth embodiment shown in FIG. 5, the bitmap subtitle stream only is multiplexed with a main A/V stream and then recorded as a main MPEG2 TS clip file on a BD-ROM. The bitmap subtitle stream is recorded in a TP format, where the packets have a unique PID distinguishable from the PIDs of the main A/V stream. In this embodiment, a text subtitle stream is supplied as a separate text subtitle file from a CP server that is connected via networks such as the Internet to the reproducing apparatus (an example of which is described in detail below with respect to FIG. 12).

To be reproduced, the text subtitle stream is uploaded on a hard disk drive (HDD) or other memory such as a RAM, flash memory, etc. and then decoded by a text processor. As shown in FIG. 5, the bitmap subtitle stream and text subtitle stream, each having different languages, may be reproduced seamlessly. It depends on the optical reproducing apparatus whether or not seamless reproduction between the text subtitle streams may be supported.

In a sixth embodiment shown in FIG. 6, the bitmap subtitle stream only is multiplexed with a main A/V stream and then recorded as a main MPEG2 TS clip file on a BD-ROM. The bitmap subtitle stream is recorded in a TP format, where the packets have a PID distinguishable from the PIDs of the main A/V stream. In this embodiment, a text subtitle stream is supplied as a separate text subtitle file from a CP server that is connected via networks such as the internet to the reproducing apparatus. Beside the text subtitle stream, another bitmap subtitle stream is supplied from the CP server as a separate bitmap subtitle file.

For the subtitle streams from the CP server to be reproduced, the streams are uploaded on a hard disk drive (HDD) or other memory such as a RAM, flash memory, etc. and then decoded by a text processor. The bitmap subtitle stream on the BD-ROM and the bitmap and text subtitle streams from the CP server may be used for the subtitles of different languages such as Korean, English, and Chinese, and may reproduced seamlessly, as shown in FIG. 6.

Other embodiments of the present invention may be created from combinations of the foregoing embodiments. For example, the bitmap subtitle streams and the text subtitle streams may be supplied from both a BD-ROM and a CP server.

A plurality of the text subtitle streams may also be written on a BD-ROM in various ways and the writing formats will be described below in detail.

As shown in FIG. 7, a plurality of text subtitle streams (text subtitle streams #1 to #n) are multiplexed with each other and are then written as a single MPEG2 TS stream clip file. Each text subtitle stream has a unique PID so that each stream may be distinguished from each other. The single MPEG2 TSP clip file may contain the total text subtitle streams or some text subtitles that need to be uploaded or downloaded.

According to the writing formats of FIG. 8, a plurality of text subtitle streams (text subtitle streams #1 to #n) are written as individual files, each being in accordance with either the MPEG2 TS stream format or non-MPEG2 TS format such as XML. In either case, each text subtitle stream is distinguishable and chosen selectively by referencing the corresponding text subtitle files so as to determine text subtitle streams to be uploaded or downloaded.

According to the writing formats of FIG. 9, a portion of a plurality of the text subtitle streams (text subtitle streams #1 to #(n−2)) are multiplexed with each other and are then written as a single MPEG2 TS stream file. Each text subtitle stream has a unique PID so that each stream may be distinguished from the other. The other portions of the plurality of the text subtitle streams (text subtitle streams #(n−1) to #n) are written as individual MPEG2 TS stream files without insertion of unique PIDs.

According to the writing formats of FIG. 10, a plurality of the text subtitle streams (text subtitle streams #1 to #n) are written as a single non-MPEG2 TS file. Each text subtitle stream may be organized separately or intermixed within the non-MPEG2 TS file.

According to the writing formats of FIG. 11, a portion of a plurality of the text subtitle streams (text subtitle streams #1 to #(n−2)) are multiplexed with each other and are then written as a single non-MPEG2 TS file. The other portion of the plurality of the text subtitle streams (text subtitle streams #(n−1) to #n) are written as individual non-MPEG2 TS files, separately.

According to the writing formats of FIG. 12, when one or more audio or bitmap subtitle streams need to be reproduced together with text subtitle streams, a plurality of the text subtitle streams (text subtitle streams #1 to #n) are multiplexed with the audio or bitmap subtitle streams and then written as a single MPEG2 TS stream clip file. In this case, a user can choose subtitle and audio selection in any combination desired, for example, Korea sound and Korean text or bitmap subtitle, English audio and Korean text or bitmap subtitle for English listening practice, or English text subtitle and Korean bitmap subtitle for multiple language subtitles.

FIG. 13 illustrates an optical disc reproducing apparatus according to an embodiment of the present invention. As shown, the apparatus includes an optical pickup 11 for reading out data from a BD-ROM 10; a source stream switch 12; a memory 13; a Java processor 14; a text subtitle processor 15; a first demultiplexer (demux) 16; a second demultiplexer (demux) 17; a presentation graphic source switch 18; a font engine 19; an interactive graphic decoder 20; a presentation graphic decoder 21; a video decoder 22; an interactive graphic data switch 23; a presentation graphic data selector 24; an interactive graphic plane 25; a presentation graphic plane 26; a video plane 27; a background plane 28; and several mixers 29, 30, 31.

The optical disc reproducing apparatus may be connected to a CP sever 300 through the internet 200. The CP server 300 supplies bitmap subtitle streams or text subtitle streams that may be in the MPEG2 TS stream format or a predetermined binary stream of XML format.

The text subtitle stream from the CP server 300 may be a multiplexed stream of multiple language text subtitle streams only or a multiplexed stream of text subtitle streams and audio streams. The bitmap or text subtitle streams supplied from the CP server are uploaded to memory 13, which is a HDD, RAM, flash memory, etc.

The decoding process of the bitmap and text subtitle streams will be described below in detail. A text subtitle stream recorded on a BD-ROM in the MPEG2 TS stream format separately from main A/V stream is read out from the BD-ROM and may then be uploaded to the memory 13. The text subtitle stream is then supplied to the text subtitle processor 15 through the source stream switch 12 and the second demux 17. The text subtitle processor 15 may be configured as a component of the Java processor 14 or a separate text processor as shown.

Based on the text subtitle stream processed by the text subtitle processor 15, font presentation graphic data are generated from the font engine 19 and then input to the presentation graphic data selector 24. Presentation graphic data corresponding to, e.g., a bitmap subtitle stream may also supplied to the presentation graphic data selector 24 from the memory 13 through the switch 12, the first demux 16 or second demux 17, the presentation graphic source switch 18 and the presentation graphic decoder 21. As will be appreciated, the presentation graphic decoder 21 decodes the presentation graphic data. The presentation graphic data selector 24 in one embodiment selectively chooses one of the presentation graphic data from the font engine 19 (text subtitle graphic data) or from the presentation graphic decoder 21 (bitmap subtitle graphic data), and supplies this data to the presentation graphic plane 26.

Meanwhile, reproduced background data (if any) is supplied by the switch 12 to a background plane 28, and reproduced A/V data is supplied by the switch 12 to the video decoder 22 via the first demux 16. The video decoder 22 decodes the A/V data. The mixer 29 mixes the decoded A/V data with the background data (if any). The mixer 30 mixes the output of the mixer 29 with the output from the presentation graphic plane 26.

In this manner, either bitmap subtitles or text subtitles may be displayed together with main video pictures. As alluded to before, both the text subtitle stream and the bitmap subtitle stream may be supplied from the CP server 300.

When a text subtitle stream has been recorded on a BD-ROM in a predefined binary format such as XML, the text subtitle stream is uploaded to the memory 13 and then supplied directly to the text subtitle processor 15 bypassing the second demux 17. Based on the output of the text subtitle processor 15, font presentation graphic data are generated from the font engine 19 and then input to the presentation graphic data selector 24. Here, either presentation graphic data from the font engine 19 (text subtitle graphic data) or from the presentation graphic decoder 21 (bitmap subtitle graphic data) is chosen selectively as output. The output of the presentation graphic data selector 24 is supplied to the presentation graphic plane 26 so that either bitmap subtitles or text subtitles may be displayed together with main video pictures. This is accomplished by mixer 30 which mixes the output from mixer 29 and the presentation graphics plane 26. Also, both or either of the text subtitle stream and bitmap subtitle streams may be supplied from the CP server 300.

Interactive graphic data such as menu selector button are supplied to the interactive graphic decoder 20 through the demux 16, and the output of the interactive graphic decoder 20 is input to the interactive graphic data switch 23. Interactive graphic data may also be supplied from the Java processor 14 and/or the font engine 19, and are input to the interactive graphic data switch 23. The interactive graphic data switch 23 determines which input is chosen as an output to the interactive graphic plane 25. The output from the interactive graphics plane 25 is then mixed by mixer 31 with the output from mixer 30.

The interactive graphic data selector 24 may be implemented as a switch or as a mixer, as shown in FIGS. 14 and 15, respectively. To be specific, while a text subtitle and a bitmap subtitle may not be displayed simultaneously if the switch embodiment is adopted, the mixer embodiment enables the two subtitles to be displayed simultaneously on non-overlapping regions of a screen. Furthermore, instead of using the interactive graphic data selector 24, a text presentation plane 40 may be additionally used as shown in FIG. 16 so as to display the text subtitle supplied from the font engine 19. As will be appreciated, this embodiment also uses an additional mixer to mix the output from the text presentation plane 40 and the mixer 31. In the configuration of FIG. 16, the text subtitles and bitmap subtitles may be displayed independently of each other.

The present invention provides a recording medium having a data structure for managing the reproduction of subtitle data, and provides methods and apparatuses for recording the data structure on the recording medium.

While the invention has been disclosed with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations there from. For example, while described with respect to a Blu-ray ROM optical disk in several instances, the present invention is not limited to this standard of optical disk or to optical disks. It is intended that all such modifications and variations fall within the spirit and scope of the invention. 

1. A method of reproducing data recorded on a recording medium, the method comprising: receiving at least one text subtitle stream from an external source, reproducing at least one subtitle stream including the at least one text subtitle stream and at least one bitmap subtitle stream recorded on the recording medium, wherein either one of the text subtitle stream and the bitmap subtitle stream is reproduced.
 2. The method of claim 1, wherein the external source includes contents provided through networks, and the text subtitle stream is received in a format of MPEG2 transport stream.
 3. The method of claim 1, further comprising: reproducing at least one video data stream, wherein the bitmap subtitle stream is multiplexed with the video data stream in a main file.
 4. The method of claim 3, wherein the bitmap subtitle stream and the text subtitle stream include transport packets having a unique packet identifier distinguishable from a packet identifier of the video data stream.
 5. The method of claim 1, wherein the bitmap subtitle stream being included in a bitmap subtitle file, the text subtitle stream being included in a text subtitle file, the bitmap subtitle file being separated from the text subtitle file.
 6. The method of claim 1, wherein the at least one text subtitle stream is included in a plurality of text subtitle files, and each text subtitle file including a single text subtitle stream, one of the plurality of text subtitle files storing the single text subtitle stream for one language, and another one of the plurality of text subtitle files storing the single text subtitle stream for a different language.
 7. An apparatus for reproducing data recorded on a recording medium, the apparatus comprising: a pickup configured to read at least one bitmap subtitle stream recorded on a recording medium, a memory configured to store at least one text subtitle stream received from an external source, a first decoder configured to decode the bitmap subtitle stream, a second decoder configured to decode the text subtitle stream, wherein either one of the text subtitle stream and the bitmap subtitle stream is reproduced.
 8. The apparatus of claim 7, wherein the external source includes contents provided through networks, and the text subtitle stream is received in a format of MPEG2 transport stream.
 9. The apparatus of claim 7, further comprising: a video decoder to decode at least one video data stream, wherein the bitmap subtitle stream is multiplexed with the video data stream in a main file.
 10. The apparatus of claim 9, wherein the bitmap subtitle stream and the text subtitle stream include transport packets having a unique packet identifier distinguishable from a packet identifier of the video data stream.
 11. The apparatus of claim 7, wherein the bitmap subtitle stream being included in a bitmap subtitle file, the text subtitle stream being included in a text subtitle file, the bitmap subtitle file being separate from the text subtitle file.
 12. The apparatus of claim 7, wherein the at least one text subtitle stream is included in a plurality of text subtitle files, and each text subtitle file including a single text subtitle stream, one of the plurality of text subtitle files storing the single text subtitle stream for one language, and another one of the plurality of text subtitle files storing the single text subtitle stream for a different language.
 13. The apparatus of claim 7, further comprising: a selector configured to reproduce either one of the text subtitle stream and the bitmap subtitle stream. 